The present invention relates to a zoom lens used on an imaging module, and an imaging apparatus including that zoom lens.
In recent years, there are mounting demands for digital cameras: they are required to have a small-format, slimmed down yet higher-zoom-ratio, wide-angle arrangement having much more pixels.
Imaging optical systems that have advantageously be used for the slimming-down of optical systems, for instance, include those disclosed in JP(A) 2003-43354 (Patent Publication 1) and JP(A) 2003-302576 (Patent Publication 2). The imaging optical system set forth in Patent Publication 1 or 2 has a reflective optical element for bending an optical path (hereinafter called simply the reflective optical element) included in the most object side lens group.
By the way, the imaging optical system using the reflective optical element is generally broken down into two types depending on whether the lens group including the reflective optical element has negative (Patent Publication 1) or positive (Patent Publication 2) refracting power.
Typical examples where the lens group including the reflective optical element, as viewed from the object side, having positive refracting power are set forth in JP(A) 2003-329930 (Patent Publication 3), JP(A) 2004-264343 (Patent Publication 4), JP(A) 2008-83125 (Patent Publication 5), JP(A) 2008-191286 (Patent Publication 6), JP(A) 2009-265553 (Patent Publication 7), JP(A) 2010-39188 (Patent Publication 8), JP(A) 2011-39101 (Patent Publication 9) and so on.
Typical examples where the lens group including the reflective optical element has negative refracting power are set forth in JP(A) 2004-69808 (Patent Publication 10), JP(A) 2004-205796 (Patent Publication 11), JP(A) 2004-348082 (Patent Publication 12), JP(A) 2010-152145 (Patent Publication 13) and so on.